CA2108245A1 - Method for treating myocardial ischemia employing serotonin receptor antagonists - Google Patents
Method for treating myocardial ischemia employing serotonin receptor antagonistsInfo
- Publication number
- CA2108245A1 CA2108245A1 CA002108245A CA2108245A CA2108245A1 CA 2108245 A1 CA2108245 A1 CA 2108245A1 CA 002108245 A CA002108245 A CA 002108245A CA 2108245 A CA2108245 A CA 2108245A CA 2108245 A1 CA2108245 A1 CA 2108245A1
- Authority
- CA
- Canada
- Prior art keywords
- ketanserin
- serotonin receptor
- cinanserin
- receptor antagonist
- vehicle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K31/00—Medicinal preparations containing organic active ingredients
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K31/00—Medicinal preparations containing organic active ingredients
- A61K31/16—Amides, e.g. hydroxamic acids
- A61K31/165—Amides, e.g. hydroxamic acids having aromatic rings, e.g. colchicine, atenolol, progabide
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K31/00—Medicinal preparations containing organic active ingredients
- A61K31/33—Heterocyclic compounds
- A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
- A61K31/435—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with one nitrogen as the only ring hetero atom
- A61K31/47—Quinolines; Isoquinolines
- A61K31/475—Quinolines; Isoquinolines having an indole ring, e.g. yohimbine, reserpine, strychnine, vinblastine
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K31/00—Medicinal preparations containing organic active ingredients
- A61K31/33—Heterocyclic compounds
- A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
- A61K31/495—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with two or more nitrogen atoms as the only ring heteroatoms, e.g. piperazine or tetrazines
- A61K31/505—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P9/00—Drugs for disorders of the cardiovascular system
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P9/00—Drugs for disorders of the cardiovascular system
- A61P9/10—Drugs for disorders of the cardiovascular system for treating ischaemic or atherosclerotic diseases, e.g. antianginal drugs, coronary vasodilators, drugs for myocardial infarction, retinopathy, cerebrovascula insufficiency, renal arteriosclerosis
Landscapes
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Medicinal Chemistry (AREA)
- Pharmacology & Pharmacy (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Epidemiology (AREA)
- Engineering & Computer Science (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Cardiology (AREA)
- Heart & Thoracic Surgery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Organic Chemistry (AREA)
- Urology & Nephrology (AREA)
- Vascular Medicine (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
Abstract
Abstract METHOD FOR TREATING MYOCARDIAL ISCHEMIA EMPLOYING
SEROTONIN RECEPTOR ANTAGONISTS
A method for treating myocardial ischemia in a mammalian species by administrating a serotonin receptor antagonist such as cinanserin, ketanserin or LY 53857.
SEROTONIN RECEPTOR ANTAGONISTS
A method for treating myocardial ischemia in a mammalian species by administrating a serotonin receptor antagonist such as cinanserin, ketanserin or LY 53857.
Description
21û824~
,~
~E~ 32~ EATI~Q NYO~/y9~yL-~gc~ EMPLOYI~Q
g~TOR ANTAGONI~ ;
This invention relates to a method for treating myocardial ischemia in mammalian species by administering a serotonin receptor antagonist, -such as cinanserin, ketanserin and LY 53857.
: :' In accordance with the present invention, a method is provided for treating myocardial ischemia ~including angina pectoris, infarction, angioplasty, etc.) in mammalian species wherein a lS serotonin receptor antagonist is systemically, such as orally or parenterally, administered in an amount effective to treat myocardial ischemia.
Any serotonin receptor antagonist may be employed as disclosed herein. Examples of such -~
serotonin receptor antagonists are disclosed in R.A. Glennon, Serotonin Receptors: Clinical Implications Neuroscience and Behavioral Reviews, 14 35-47, 1990; and 5-Hydroxytryptamine Receptors, -Pharmacological Reviews, vol. 44, No. 3, 1992, which are incorporated by reference herein.
Preferred serotonin receptor antagonists include cinan~erin, ketanserin and LY 53857.
The compounds of formula I can be formulated for use in the present methods in compositions such as tablets, capsules or elixirs for oral administration, or in sterile solutions or suspensions for parenteral administration. The ~. .
21~4~
compounds of formula I may also be administered via - transdermal patch or nasal inhalation solutions.
About 10 to 500 milligrams of a compound of formula I is compounded with physiologically acceptable vehicle, carrier, excipient, binder, preservative, stabilizer, flavor, etc., in a unit dosage form as called for by accepted pharmaceutical practice.
The amount of active substance in these compositions or preparations is such that a suitable dosage in the range indicated is obtained.
The dose administered must be carefully adjusted according to age, weight and condition of the patient, as well as the route of administration, dosage form and regimen and the desired result.
The compositions described above may be administered in the dosage forms as described above in single or divided doses of one to four times daily.
Many of the active substances described above form commonly known, pharmaceutically acceptable salts such as alkali metal and other common basic salts or acid addition salts, etc.
References to the base substances are therefore intended to include those common salts known to be substantially equivalent to the parent compound.
Figure 1 is a graph showing the effect of the serotonin receptor antagonists ketanserin, cinanserin and LY 53857 on time to contracture (~ercent change relative to vehicle) in globally ischemic rat hearts.
, . ~, 21~24~
",, Figures 2A to 2C are graphs showing the effect of the serotonin receptor antagonists cinanserin (Cinan), ketanserin (Ket) and LY 53, 857 respectively on cumulative LDH release during 5 reperfusion following 25 minutes of global ischemia in isolated rat hearts. All compounds significantly reduced LDH release (*, p<O.05) compared to vehicle. Ketanserin given only during reperfusion (Reper) did not cause a reduction in LDH release.
Figure 3 iS a graph showing the effect of serotonin (S) on time to contracture in globally ischemic, isolated rat hearts. Serotonin significantly reduced time to contracture compared 15 to vehicle (~, p<O.O5) at 30 and lOO~M. Ketanserin (Ket) and cinanserin (Cin) abolished the pro-ischemic effect of serotonin.
Figure 4 is a graph showing the effect of 150 (i.p.) parachlorophenylalanine (PCPA) pretreatment on time to contracture in globally ischemic rat hearts. Parachlorophenylalanine significantly increased time to contracture in these hearts when compared to vehicle (*, p<0.05).
Figures 5A to 5D are graphs showing the effect of prazosin, ketanserin, cinanserin and LY
53857, respectively, on methoxamine-induced contraction in rat aortic rings.
The following examples and preparations describe the manner and process of making and using the preferred embodiments of the invention and are illustrative rather than limiting. It should be understood that there may be other embodiments which fall within the spirit and scope of the ;
invention as defined by the claims appended hereto. ~ J' ~
~ - , - 21~2~
ExamDle To determine the effect of serotonin receptor agonists and antagonists, male Sprague-Dawley rats (450-550 g) were prepared as described below. The rats were anesthetized using 100 mg/kg sodium pentobarbital (i.p.). They were intubated and then treated with i.v. heparin (1000 U/kg).
While being mechanically ventilated, their hearts were perfused in situ via retrograde cannulation of the aorta. The hearts were then excised and quickly moved to a Langendorff apparatus where they were perfused with Krebs-henseleit bicarbonate buffer solution (~mM): 112 NaCl, 25 NaHCO3, 5 KCl, 1.2 MgSO4, 1 KH2PO4, 1.25 CaCl2, 2 pyruvate and 11.5 dextrose bubbled with 95% 2 - 5% CO2) at a constant perfusion pressure (85 mm Hg). A
water-filled latex balloon attached to a metal cannula was then inserted into the left ~entricle and connected to a 5tatham pressure transducer for measurement of left ventricular pressure. The hearts were allowed to equilibrate for 15 min, at which time end diastolic pressure (EDP) was adjusted to 5 mm Hg and this balloon volume was maintained for the duration of the experiment.
Pre-ischemia or pre-drug function, heart rate and coronary flow ~extracorporeal electromagnetic flow probe) were then measured. Left ventricular developed pressure ~LVDP) was calculated from the difference between left ventricular peak systolic pressure and EDP. Cardiac temperature was maintained throughout the experiment by submerging the hearts in 37C buffer which was allowed to accumulate in a stoppered, heated chamber. -~
, , : ' i.:.~ :, ' - 5 _ 2~82~5 The model of global ischemia in isolated rat hearts was designed such that any protective effects observed are generally due to a direct cardioprotective effect and not to effects on 5 cornonary or peripheral vascular tone. Also, '' because the hearts are perfused with an oxygenated buffer solution, platelets or the normal components of an inflammatory response are probably not important mediators of the ischemic/reperfusion injury observed in this model. It was found that agents which exert their protective effects directly on ischemic myocardium are generall~
efficacious in this model and such agents include calcium antagonists, ATP-sensitive potassium channel openers and calmodulin inhibitors. Agents which exert their protective effects either through their effects on the peripheral or coronary vasculature such as nitrates or agents which act on blood or act on some component of the inflammatory response such as thromboxane A2 receptor antagonists are generally ineffective in this model.
Ef~ect of 5HT rece~tor aqonists an~ ~anta~o~L~s~
The hearts were divided into the following groups: 1. Vehicle (0.1% DMSO) treatment beginning 10 minutes before the onset of ischemia (n = 8). 2. 0.3-10 ~M ketanserin treatment beginning 10 minutes before the onset of ischemia In = 4-5 per group). 3. 10 ~M ketanserin gi~en only during reperfusion ~n = 4). 4. 0.1-10 ~M
cinanserin treatment beginning 10 minutes before global ischemia (n = 4-10). 5. 1-10 ~M ~Y 53857 , , treatment beginning 10 minutes before the onset of - ~;
~' ' '~' ,: : . .. .
210~2~
ischemia (n = 4 per group). After 10 minutes of ~ -vehicle or drug pretreatment, the hearts were subjected to 25 minutes of total global ischemia which was initiated by shutting off the perfusate S flow. Reperfusion was begun (without drug except in the case of group 3 above) and allowed to continue for 30 minutes. At this time, final measurements of EDP, LVDP and coronary flow were obtained. Cumulative LDH relase was measured in the reperfusate and was used as the index of cellular and membrane viability. In all hearts, the time to contracture during ischemia was measured and used as an index of cardioprotection during ischemia. Time to contracture is defined as the time (minutes) necessary for the first 5 mm Hg increase in EDP to occur during global ischemia.
The data were expressed as the percent change in time to contracture from vehicle. The potency was expressed as the concentration (~M) of the respective drug which increased the time to contracture 25% above vehicle group values (EC2s).
In another series of hearts, the effect of 5HT on the severity of ischemia was determined.
The groups were divided as follows~ 100 ~M
SHT was given 10 minutes before ischemia (n = 4 per group). 2. 30 ~M 5HT + 3 ~M ketanserin, both given 10 minutes before ischemia (n = 4). 3. 30 ; -~M 5HT + 30 ~M cinanserin, both given 10 minutes before the onset of ischemia (n = 4). 4. Vehicle (0.1% DMSO) given 10 minutes before ischemia (n =
5). The hearts were subjec~ed to global ischemia as described above and time to contracture determined. Reperfusion function and LDH release were not determined in this group.
. '` ~ '. , .
210824~ ~:
The effects of the 5HT2 antagonists cinanserin, ketanserin and LY 53857 on time to contracture during global ischemia are shown in Figure 1. These data are expressed as the percent change in the time necessary for the first 5 mm Hg change in EDP relative to vehicle. AS can be seen in this figure, all three compounds increased time to contracture in a concentration dependent manner Cinanserin was the most potent in increasing time to contracture with an EC2s of 1.6 ~t~ followed by ketanserin (EC2s = 5.5 ~) and LY 53857 (EC2s = 6.1 ~ t).
The effect of the 5HT2 antagonists on pre-ischemic and post-ischemic cardiac function is shown in Tables 1 to 3. Table 1 shows the effects -of cinanserin on cardiac function and coronary flow before and after Ischemia in isolated rat hearts.
q!AB~ 1 ~ ~-Pre-I~chemla 30 Min Post-Pre-Drug Post-Drug Reperfusion ~ . , 25 Vehicle 289i7 275i9 259ilO
0.1 ~ Cinanserin 267il7 254il8 251i9 0.3 ~ Cinanserin 285+8 258i6 260i42 1 ~t Cinanserin 255i22 234ilO 263i7 -~
,~
~E~ 32~ EATI~Q NYO~/y9~yL-~gc~ EMPLOYI~Q
g~TOR ANTAGONI~ ;
This invention relates to a method for treating myocardial ischemia in mammalian species by administering a serotonin receptor antagonist, -such as cinanserin, ketanserin and LY 53857.
: :' In accordance with the present invention, a method is provided for treating myocardial ischemia ~including angina pectoris, infarction, angioplasty, etc.) in mammalian species wherein a lS serotonin receptor antagonist is systemically, such as orally or parenterally, administered in an amount effective to treat myocardial ischemia.
Any serotonin receptor antagonist may be employed as disclosed herein. Examples of such -~
serotonin receptor antagonists are disclosed in R.A. Glennon, Serotonin Receptors: Clinical Implications Neuroscience and Behavioral Reviews, 14 35-47, 1990; and 5-Hydroxytryptamine Receptors, -Pharmacological Reviews, vol. 44, No. 3, 1992, which are incorporated by reference herein.
Preferred serotonin receptor antagonists include cinan~erin, ketanserin and LY 53857.
The compounds of formula I can be formulated for use in the present methods in compositions such as tablets, capsules or elixirs for oral administration, or in sterile solutions or suspensions for parenteral administration. The ~. .
21~4~
compounds of formula I may also be administered via - transdermal patch or nasal inhalation solutions.
About 10 to 500 milligrams of a compound of formula I is compounded with physiologically acceptable vehicle, carrier, excipient, binder, preservative, stabilizer, flavor, etc., in a unit dosage form as called for by accepted pharmaceutical practice.
The amount of active substance in these compositions or preparations is such that a suitable dosage in the range indicated is obtained.
The dose administered must be carefully adjusted according to age, weight and condition of the patient, as well as the route of administration, dosage form and regimen and the desired result.
The compositions described above may be administered in the dosage forms as described above in single or divided doses of one to four times daily.
Many of the active substances described above form commonly known, pharmaceutically acceptable salts such as alkali metal and other common basic salts or acid addition salts, etc.
References to the base substances are therefore intended to include those common salts known to be substantially equivalent to the parent compound.
Figure 1 is a graph showing the effect of the serotonin receptor antagonists ketanserin, cinanserin and LY 53857 on time to contracture (~ercent change relative to vehicle) in globally ischemic rat hearts.
, . ~, 21~24~
",, Figures 2A to 2C are graphs showing the effect of the serotonin receptor antagonists cinanserin (Cinan), ketanserin (Ket) and LY 53, 857 respectively on cumulative LDH release during 5 reperfusion following 25 minutes of global ischemia in isolated rat hearts. All compounds significantly reduced LDH release (*, p<O.05) compared to vehicle. Ketanserin given only during reperfusion (Reper) did not cause a reduction in LDH release.
Figure 3 iS a graph showing the effect of serotonin (S) on time to contracture in globally ischemic, isolated rat hearts. Serotonin significantly reduced time to contracture compared 15 to vehicle (~, p<O.O5) at 30 and lOO~M. Ketanserin (Ket) and cinanserin (Cin) abolished the pro-ischemic effect of serotonin.
Figure 4 is a graph showing the effect of 150 (i.p.) parachlorophenylalanine (PCPA) pretreatment on time to contracture in globally ischemic rat hearts. Parachlorophenylalanine significantly increased time to contracture in these hearts when compared to vehicle (*, p<0.05).
Figures 5A to 5D are graphs showing the effect of prazosin, ketanserin, cinanserin and LY
53857, respectively, on methoxamine-induced contraction in rat aortic rings.
The following examples and preparations describe the manner and process of making and using the preferred embodiments of the invention and are illustrative rather than limiting. It should be understood that there may be other embodiments which fall within the spirit and scope of the ;
invention as defined by the claims appended hereto. ~ J' ~
~ - , - 21~2~
ExamDle To determine the effect of serotonin receptor agonists and antagonists, male Sprague-Dawley rats (450-550 g) were prepared as described below. The rats were anesthetized using 100 mg/kg sodium pentobarbital (i.p.). They were intubated and then treated with i.v. heparin (1000 U/kg).
While being mechanically ventilated, their hearts were perfused in situ via retrograde cannulation of the aorta. The hearts were then excised and quickly moved to a Langendorff apparatus where they were perfused with Krebs-henseleit bicarbonate buffer solution (~mM): 112 NaCl, 25 NaHCO3, 5 KCl, 1.2 MgSO4, 1 KH2PO4, 1.25 CaCl2, 2 pyruvate and 11.5 dextrose bubbled with 95% 2 - 5% CO2) at a constant perfusion pressure (85 mm Hg). A
water-filled latex balloon attached to a metal cannula was then inserted into the left ~entricle and connected to a 5tatham pressure transducer for measurement of left ventricular pressure. The hearts were allowed to equilibrate for 15 min, at which time end diastolic pressure (EDP) was adjusted to 5 mm Hg and this balloon volume was maintained for the duration of the experiment.
Pre-ischemia or pre-drug function, heart rate and coronary flow ~extracorporeal electromagnetic flow probe) were then measured. Left ventricular developed pressure ~LVDP) was calculated from the difference between left ventricular peak systolic pressure and EDP. Cardiac temperature was maintained throughout the experiment by submerging the hearts in 37C buffer which was allowed to accumulate in a stoppered, heated chamber. -~
, , : ' i.:.~ :, ' - 5 _ 2~82~5 The model of global ischemia in isolated rat hearts was designed such that any protective effects observed are generally due to a direct cardioprotective effect and not to effects on 5 cornonary or peripheral vascular tone. Also, '' because the hearts are perfused with an oxygenated buffer solution, platelets or the normal components of an inflammatory response are probably not important mediators of the ischemic/reperfusion injury observed in this model. It was found that agents which exert their protective effects directly on ischemic myocardium are generall~
efficacious in this model and such agents include calcium antagonists, ATP-sensitive potassium channel openers and calmodulin inhibitors. Agents which exert their protective effects either through their effects on the peripheral or coronary vasculature such as nitrates or agents which act on blood or act on some component of the inflammatory response such as thromboxane A2 receptor antagonists are generally ineffective in this model.
Ef~ect of 5HT rece~tor aqonists an~ ~anta~o~L~s~
The hearts were divided into the following groups: 1. Vehicle (0.1% DMSO) treatment beginning 10 minutes before the onset of ischemia (n = 8). 2. 0.3-10 ~M ketanserin treatment beginning 10 minutes before the onset of ischemia In = 4-5 per group). 3. 10 ~M ketanserin gi~en only during reperfusion ~n = 4). 4. 0.1-10 ~M
cinanserin treatment beginning 10 minutes before global ischemia (n = 4-10). 5. 1-10 ~M ~Y 53857 , , treatment beginning 10 minutes before the onset of - ~;
~' ' '~' ,: : . .. .
210~2~
ischemia (n = 4 per group). After 10 minutes of ~ -vehicle or drug pretreatment, the hearts were subjected to 25 minutes of total global ischemia which was initiated by shutting off the perfusate S flow. Reperfusion was begun (without drug except in the case of group 3 above) and allowed to continue for 30 minutes. At this time, final measurements of EDP, LVDP and coronary flow were obtained. Cumulative LDH relase was measured in the reperfusate and was used as the index of cellular and membrane viability. In all hearts, the time to contracture during ischemia was measured and used as an index of cardioprotection during ischemia. Time to contracture is defined as the time (minutes) necessary for the first 5 mm Hg increase in EDP to occur during global ischemia.
The data were expressed as the percent change in time to contracture from vehicle. The potency was expressed as the concentration (~M) of the respective drug which increased the time to contracture 25% above vehicle group values (EC2s).
In another series of hearts, the effect of 5HT on the severity of ischemia was determined.
The groups were divided as follows~ 100 ~M
SHT was given 10 minutes before ischemia (n = 4 per group). 2. 30 ~M 5HT + 3 ~M ketanserin, both given 10 minutes before ischemia (n = 4). 3. 30 ; -~M 5HT + 30 ~M cinanserin, both given 10 minutes before the onset of ischemia (n = 4). 4. Vehicle (0.1% DMSO) given 10 minutes before ischemia (n =
5). The hearts were subjec~ed to global ischemia as described above and time to contracture determined. Reperfusion function and LDH release were not determined in this group.
. '` ~ '. , .
210824~ ~:
The effects of the 5HT2 antagonists cinanserin, ketanserin and LY 53857 on time to contracture during global ischemia are shown in Figure 1. These data are expressed as the percent change in the time necessary for the first 5 mm Hg change in EDP relative to vehicle. AS can be seen in this figure, all three compounds increased time to contracture in a concentration dependent manner Cinanserin was the most potent in increasing time to contracture with an EC2s of 1.6 ~t~ followed by ketanserin (EC2s = 5.5 ~) and LY 53857 (EC2s = 6.1 ~ t).
The effect of the 5HT2 antagonists on pre-ischemic and post-ischemic cardiac function is shown in Tables 1 to 3. Table 1 shows the effects -of cinanserin on cardiac function and coronary flow before and after Ischemia in isolated rat hearts.
q!AB~ 1 ~ ~-Pre-I~chemla 30 Min Post-Pre-Drug Post-Drug Reperfusion ~ . , 25 Vehicle 289i7 275i9 259ilO
0.1 ~ Cinanserin 267il7 254il8 251i9 0.3 ~ Cinanserin 285+8 258i6 260i42 1 ~t Cinanserin 255i22 234ilO 263i7 -~
3 ~ Cinanserin 294i7 271i8 280l4 ~ -10 ~ Cinanserin 264+12 184i29a~b 237il2 ~VDP ~mmHtg) Vehicle 140i3 140i2 31i4~ `
0.1 ~ Cinanserin 143i3 126i7 30i8a 0.3 ~ Cinanserin 139i2 135i5 65ill~b -1 ~M Cinanserin 144i9 14115 77i6 3 ~t Cinanserin 136i6 123i6 78i9~b 10 ~M Cinanserin 144i3 133i6 73i6a~b ., .
21~g2~
Co~Qnarv Flow ~mL/min/g) - Vehicle 17+1 16+1 12il~
0.1 ~M Cinanserin 18+1 15~1 15~1 0.3 ~M Cinanserin 21+~ l9i2 l9ilb 1 ~M Cinanserin 22+3 20~3 20+3b 3 ~M Cinanserin 21+3 20i2 20i2b 10 ~M Cinanserin 17~1 15il 12ila 10 All values are mean iSE; HR=Heart Rate;
LVDP = Left Ventricular Developed Pressure A Significantly different from itS respective predrug value (P<0.05) b Significantly different from its respective vehicle groups (P<0.05) As shown in Table 1 above, cinanserin had little effect on preischemic heart ra5e or LVDP. Only at the 10 ~M concentration was significant bradycardia observed. Despite the bradycardia seen at this concentration, no significant effect on LVDP was found. No significant effect on pre-ischemic coronary flow was seen for any concentration of cinanserin tested, although a slight reduction was ;~
observed at several concentrations. Recovery of cardiac function was also measured at 30 minutes after the initiation of reperfusion. In vehicle `
treated hearts, significant reperfusion contractile dysfunction was observed, indicating severe ischemic/reperfusion injury. Cinanserin significantly improved reperfusion LVDP at 0.3 ~M
and higher concentrations when compared to vehicle controls, although this effect did not appear to be clearly concentration related. Coronary flow was significantly reduced (relative to pre-ischemic baseline values) during reperfusion in vehicle treated animals and cinanserin significantly ` " ~` ' ~ : . '' :
~, :`, . ' 1 : . ` ,: . ' ` HA616 .. ~ g improved reflow at cardioprotective concentrations, except at the 10 ~M concentration. In Figure 2A, the effect of cinanserin on reperfusion LDH release is shown. Significant reductions in LDH were S observed for 1-lO ~M cinanserin compared to vehicle. The reductions in LDH release were not found to be concentration related. Nonischemic hearts did not release LDH and historically, LDH
has never been found to be released from isolated rat hearts which were not ischemic within the time frame of the experiments.
Cardiac function and coronary flow data for ketanserin and LY 53857 are shown in Tables 2 and 3.
TAB~ 2 30 Min Post-Pre-Drug Post-Drug Reperfusion ~R. (be~SakiLi ~ehicle 289+7 275+9 259+10~ :
0.3 ~M Ketanserin 291i2 275i6 266+18a 1 ~M Ketanserin 311il6 272ill 243i35a i:~
3 ~M Ketanserin 310il3 244~16a 246i22a 25 10 ~M Ketanserin 290i6 196il9a~b 220+22~
3 ~M Ketanserin~Reper) 292il5 285+11 196il4il~b ~VDP (mmH~
Vehicle 140i3 140i2 31+4 30 0.3 ~M Ketanserin 146i5 141+10 20+5~
1 ~M Ketanserin 130i6 128ig 29i5a 3 ~M Ketanserin 128i8 127+9 53+7a,b 10 ~M Ketanserin 135+5 128+5 66+4~b 3 ~M Ketanserin~Reper) 134i4 130iS 33+6a ~ ~:
:.
~oronary plow ~mL/minl9~
Vehicle 17+1 1611 12ila : :~ ::::
0.3 ~M Ketanserin 20i2 16+2 13+2~ : :
1 ~M Ketanserin 19~1 l5il lOila 40 3 ~M Ketangerin 19+1 lS+l 13ilA
10 ~M Ketanserin l9il 14_2 13+2i~
3 ~M Ketanserin~Reper) l9il 17i2 14ilA
: .~:
` HA616 : ':
21082~a TABIlE ~
Pre-IBche~l~
30 ~in Post-Pre-Drug Post-Drug Reperfusion HR (beat~,~m~L
Vehicle 289i7 275i9 259+10 1 ~M LY 53857 270i5 257i6 230i25 3 ~M LY 53857 274+5 265+8 240il3 10 ~M LY 53857 288+10 252il2~ 250+4 .
LVDP ~mm~) Vehicle 140i3 1~0+2 31i4a 1 ~M LY 53857 141+4 132i6 23+5a 3 ~M LY 53857 148i6 144i6 73~7a,b 10 ~M LY 53857 130i5 123i5 86+6a,b CorQn~y_EloW (mL/minL~L
Vehicle 17il 16il 12ila 1 ~M LY 53857 17+1 l5il 12ila 3 ~M LY 53857 17+1 17+1 13ila 10 ~M LY 53857 20i3 21i3 15i3 For Tables 2 and 3, all values are mean iSE;
HR=Heart Rate; LVDP = Left Ventricular Developed : -Pressure Significantly different from its respective predrug value (P<O. 05) b Significantly different from its respective vehicle groups (P<0.05J
Neither ketanserin nor LY 53857 exerted marked pre-ischemic effects on cardiac function. Ketanserin caused bradycardia at the 3 and 10 ~M
concentrations without affecting LVDP. Ketanserin seemed to exert a moderate coronary constrictor effect in nonischemic hearts while LY 53857 was devoid of significant effects. Both compounds ~0 significantly improved reperfusion LVDP starting at 3 ~M. Reperfusion flow was not improved by ' ~ . ' '.' .. '.',' !, .;,'. ~ , . ; . .......... . .
. ' '' ~" ,' ' . :
2lns24~
ketanserin nor by LY 53857. LDH data for ketanserin and LY 53857 are shown in Figures 2B and 2C, respectively. As can be seen in these figures, ketanserin only significantly reduced ~DH relase at the 10 ~M concentration while LY 53857 significantly reduced it at 3 and 10 ~M
concentrations. Ketanserin was also given only during reperfusion at 3 ~M and no protective effect was observed for any variable measured.
The effect of 5HT on time to contracture is shown in Figure 3. SHT was found to significantly decrease time to contracture at >30 ~M, indicating a pro-ischemic effect. The 1 and IO ~M
concentrations were without any measurable effect ~ i 15 on the severity of ischemia ~data for 1 ~M 5HT is ~- -not shown in Figure 3). The 5HT2 receptor antagonists cinanserin and ketanserin completely abolished this pro-ischemic effect. The effect of 5HT on pre-ischemic cardiac function and coronary -~
flow is shown in Table 4.
5aa~ 4 Pre-Drug Post-Drug ~ lhfALslmi~
Vehicle 302+15 295+13 1 ~M SHT 273+7 276+5 10 ~M SHT 300+7 294ill 30 ~M 5HT 281+15 319+20 100 ~M SHT 298ilO 369+19~b :
30 ~M SHT ~ 3 ~M Ketanserin 270+16 335il7~
30 ~M 5HT + 1 ~M Cinanserin 297+9 340+11~b LVDP ~mmH~g) ~
Vehicle 122+5 121_7 ~ ~-1 ~M 5HT 145i4 141i3 10 ~M SHT 135+4 132i7 30 ~M 5HT 117+5 103+11 100 ~M 5HT 121i8 88i8~b 30 ~M 5HT ~ 3 ~M Ketanserin 141+4 130*2 30 ~M SHT + 1 ~M Cinanserin 139+7 122+5 . ~ . ., ~. . .; ~ , " . . I - ,. . .. . .
: - `
210824~
Corona~ Fl~
Vehicle 19+2 18~2 1 ~M SHT 16il 16+1 10 ~M 5HT 19+2 20+2 5 30 ~M $HT 16+1 14~1 -100 ~M SHT 16_2 15+3 . - -30 ~M SHT , 3 ~M Ketanserin 18$2 18+1 30 ~iM SHT + 1 ~M Cinanserin 19+1 18+1 -10 All values are mean ~SE; HR=Heart Rate;
~VDP = Left ventricular Developed Pressure Significantly different from its respective predrug value ~P~0.05) ~ ~
b Significantly different from its respective ~ -~ -s vehicle groups ~P<0.05) .~
.. -.... ~"
SHT increased heart rate in a concentration dependent manner. Along with tachycardia, SHT
reduced ~VDP, although this was only observed at the 100 ~M concentration. Typically, slight negative inotropy in rat hearts subjected to tachycardia is observed. Ketanserin and cinanserin only partially abolished the tachycardia. No significant effect on coronary flow was observed.
Effect of Parachlorophenylalanine on Ischemic Hearts To determine if endogenous 5H~ is mediating 30 a pro-ischemic effect in isolated hearts, rats, ~-prepared as described below were treated with parachlorophenylalanine. Parachlorophenylalanine depletes brain and peripheral 5HT by inhibition of tryptophan hydroxylase, the rate limiting step in SHT synthesis. The treatment regimen of parachlorophenylalanine use was found previously to significantly deplete SHT. Male Sprague-Dawely .
.. ..
, 210~2~
rats (450-550 g) we-e injected with i.p. 105 mg/kg parachlorophenylalanine (n = 10) or its vehicle (water, n = 6) on three consecutive days. On the fourth day, the rats were anesthetized with 100 mg/kg sodium pentobarbital. The hearts were then excised and moved to an isolated heart apparatus as described above. trhe hearts were then subjected to 25 minutes to global ischemia and 30 minutes of `
reperfusion. Time to contracture, recovery of 10 contractile function, coronary flow and cumulative -~
LDH release were measured as described above. ~-~
Time to contracture data are shown in Figure 4. As can be seen parachlorophenyltalanine~(PCPA) .
significantly incareased the time to contracture in these hearts, indicating a protective effect. The effect of parachlorophenylalanine on pre-ischemic and post-ischemic cardiac function and coronary flow is shown in Table 5.
~ 5 30 Min. Post~
Pre-Ischemia Ischemia ~ (beat~min Vehicle 257ilO 200+35a ~ :~
PCPA 271+8 275+8b ~VDP (mmH~
Vehicle 139+3 18ilt~
PCPA 128ill 60i7a,b Corona~y Flow (mL/min/~) Vehicle 16il 9ila PCPA 18il 18*2b LD~ ~ ( u / c~ ) Vehicle - 21~2 PCPA - 15i2b .~ .
~,t ~ t ~7~ t~ ~ t~t~t~ !i t~ ~ t~ ,t~
.
2i~245 ,, All values are mean +SE; HR=Heart Rate;
LVDP = Left Ventricular Developed Pressure a Significantly different from its respective predrug value ~P<0.05J
0.1 ~ Cinanserin 143i3 126i7 30i8a 0.3 ~ Cinanserin 139i2 135i5 65ill~b -1 ~M Cinanserin 144i9 14115 77i6 3 ~t Cinanserin 136i6 123i6 78i9~b 10 ~M Cinanserin 144i3 133i6 73i6a~b ., .
21~g2~
Co~Qnarv Flow ~mL/min/g) - Vehicle 17+1 16+1 12il~
0.1 ~M Cinanserin 18+1 15~1 15~1 0.3 ~M Cinanserin 21+~ l9i2 l9ilb 1 ~M Cinanserin 22+3 20~3 20+3b 3 ~M Cinanserin 21+3 20i2 20i2b 10 ~M Cinanserin 17~1 15il 12ila 10 All values are mean iSE; HR=Heart Rate;
LVDP = Left Ventricular Developed Pressure A Significantly different from itS respective predrug value (P<0.05) b Significantly different from its respective vehicle groups (P<0.05) As shown in Table 1 above, cinanserin had little effect on preischemic heart ra5e or LVDP. Only at the 10 ~M concentration was significant bradycardia observed. Despite the bradycardia seen at this concentration, no significant effect on LVDP was found. No significant effect on pre-ischemic coronary flow was seen for any concentration of cinanserin tested, although a slight reduction was ;~
observed at several concentrations. Recovery of cardiac function was also measured at 30 minutes after the initiation of reperfusion. In vehicle `
treated hearts, significant reperfusion contractile dysfunction was observed, indicating severe ischemic/reperfusion injury. Cinanserin significantly improved reperfusion LVDP at 0.3 ~M
and higher concentrations when compared to vehicle controls, although this effect did not appear to be clearly concentration related. Coronary flow was significantly reduced (relative to pre-ischemic baseline values) during reperfusion in vehicle treated animals and cinanserin significantly ` " ~` ' ~ : . '' :
~, :`, . ' 1 : . ` ,: . ' ` HA616 .. ~ g improved reflow at cardioprotective concentrations, except at the 10 ~M concentration. In Figure 2A, the effect of cinanserin on reperfusion LDH release is shown. Significant reductions in LDH were S observed for 1-lO ~M cinanserin compared to vehicle. The reductions in LDH release were not found to be concentration related. Nonischemic hearts did not release LDH and historically, LDH
has never been found to be released from isolated rat hearts which were not ischemic within the time frame of the experiments.
Cardiac function and coronary flow data for ketanserin and LY 53857 are shown in Tables 2 and 3.
TAB~ 2 30 Min Post-Pre-Drug Post-Drug Reperfusion ~R. (be~SakiLi ~ehicle 289+7 275+9 259+10~ :
0.3 ~M Ketanserin 291i2 275i6 266+18a 1 ~M Ketanserin 311il6 272ill 243i35a i:~
3 ~M Ketanserin 310il3 244~16a 246i22a 25 10 ~M Ketanserin 290i6 196il9a~b 220+22~
3 ~M Ketanserin~Reper) 292il5 285+11 196il4il~b ~VDP (mmH~
Vehicle 140i3 140i2 31+4 30 0.3 ~M Ketanserin 146i5 141+10 20+5~
1 ~M Ketanserin 130i6 128ig 29i5a 3 ~M Ketanserin 128i8 127+9 53+7a,b 10 ~M Ketanserin 135+5 128+5 66+4~b 3 ~M Ketanserin~Reper) 134i4 130iS 33+6a ~ ~:
:.
~oronary plow ~mL/minl9~
Vehicle 17+1 1611 12ila : :~ ::::
0.3 ~M Ketanserin 20i2 16+2 13+2~ : :
1 ~M Ketanserin 19~1 l5il lOila 40 3 ~M Ketangerin 19+1 lS+l 13ilA
10 ~M Ketanserin l9il 14_2 13+2i~
3 ~M Ketanserin~Reper) l9il 17i2 14ilA
: .~:
` HA616 : ':
21082~a TABIlE ~
Pre-IBche~l~
30 ~in Post-Pre-Drug Post-Drug Reperfusion HR (beat~,~m~L
Vehicle 289i7 275i9 259+10 1 ~M LY 53857 270i5 257i6 230i25 3 ~M LY 53857 274+5 265+8 240il3 10 ~M LY 53857 288+10 252il2~ 250+4 .
LVDP ~mm~) Vehicle 140i3 1~0+2 31i4a 1 ~M LY 53857 141+4 132i6 23+5a 3 ~M LY 53857 148i6 144i6 73~7a,b 10 ~M LY 53857 130i5 123i5 86+6a,b CorQn~y_EloW (mL/minL~L
Vehicle 17il 16il 12ila 1 ~M LY 53857 17+1 l5il 12ila 3 ~M LY 53857 17+1 17+1 13ila 10 ~M LY 53857 20i3 21i3 15i3 For Tables 2 and 3, all values are mean iSE;
HR=Heart Rate; LVDP = Left Ventricular Developed : -Pressure Significantly different from its respective predrug value (P<O. 05) b Significantly different from its respective vehicle groups (P<0.05J
Neither ketanserin nor LY 53857 exerted marked pre-ischemic effects on cardiac function. Ketanserin caused bradycardia at the 3 and 10 ~M
concentrations without affecting LVDP. Ketanserin seemed to exert a moderate coronary constrictor effect in nonischemic hearts while LY 53857 was devoid of significant effects. Both compounds ~0 significantly improved reperfusion LVDP starting at 3 ~M. Reperfusion flow was not improved by ' ~ . ' '.' .. '.',' !, .;,'. ~ , . ; . .......... . .
. ' '' ~" ,' ' . :
2lns24~
ketanserin nor by LY 53857. LDH data for ketanserin and LY 53857 are shown in Figures 2B and 2C, respectively. As can be seen in these figures, ketanserin only significantly reduced ~DH relase at the 10 ~M concentration while LY 53857 significantly reduced it at 3 and 10 ~M
concentrations. Ketanserin was also given only during reperfusion at 3 ~M and no protective effect was observed for any variable measured.
The effect of 5HT on time to contracture is shown in Figure 3. SHT was found to significantly decrease time to contracture at >30 ~M, indicating a pro-ischemic effect. The 1 and IO ~M
concentrations were without any measurable effect ~ i 15 on the severity of ischemia ~data for 1 ~M 5HT is ~- -not shown in Figure 3). The 5HT2 receptor antagonists cinanserin and ketanserin completely abolished this pro-ischemic effect. The effect of 5HT on pre-ischemic cardiac function and coronary -~
flow is shown in Table 4.
5aa~ 4 Pre-Drug Post-Drug ~ lhfALslmi~
Vehicle 302+15 295+13 1 ~M SHT 273+7 276+5 10 ~M SHT 300+7 294ill 30 ~M 5HT 281+15 319+20 100 ~M SHT 298ilO 369+19~b :
30 ~M SHT ~ 3 ~M Ketanserin 270+16 335il7~
30 ~M 5HT + 1 ~M Cinanserin 297+9 340+11~b LVDP ~mmH~g) ~
Vehicle 122+5 121_7 ~ ~-1 ~M 5HT 145i4 141i3 10 ~M SHT 135+4 132i7 30 ~M 5HT 117+5 103+11 100 ~M 5HT 121i8 88i8~b 30 ~M 5HT ~ 3 ~M Ketanserin 141+4 130*2 30 ~M SHT + 1 ~M Cinanserin 139+7 122+5 . ~ . ., ~. . .; ~ , " . . I - ,. . .. . .
: - `
210824~
Corona~ Fl~
Vehicle 19+2 18~2 1 ~M SHT 16il 16+1 10 ~M 5HT 19+2 20+2 5 30 ~M $HT 16+1 14~1 -100 ~M SHT 16_2 15+3 . - -30 ~M SHT , 3 ~M Ketanserin 18$2 18+1 30 ~iM SHT + 1 ~M Cinanserin 19+1 18+1 -10 All values are mean ~SE; HR=Heart Rate;
~VDP = Left ventricular Developed Pressure Significantly different from its respective predrug value ~P~0.05) ~ ~
b Significantly different from its respective ~ -~ -s vehicle groups ~P<0.05) .~
.. -.... ~"
SHT increased heart rate in a concentration dependent manner. Along with tachycardia, SHT
reduced ~VDP, although this was only observed at the 100 ~M concentration. Typically, slight negative inotropy in rat hearts subjected to tachycardia is observed. Ketanserin and cinanserin only partially abolished the tachycardia. No significant effect on coronary flow was observed.
Effect of Parachlorophenylalanine on Ischemic Hearts To determine if endogenous 5H~ is mediating 30 a pro-ischemic effect in isolated hearts, rats, ~-prepared as described below were treated with parachlorophenylalanine. Parachlorophenylalanine depletes brain and peripheral 5HT by inhibition of tryptophan hydroxylase, the rate limiting step in SHT synthesis. The treatment regimen of parachlorophenylalanine use was found previously to significantly deplete SHT. Male Sprague-Dawely .
.. ..
, 210~2~
rats (450-550 g) we-e injected with i.p. 105 mg/kg parachlorophenylalanine (n = 10) or its vehicle (water, n = 6) on three consecutive days. On the fourth day, the rats were anesthetized with 100 mg/kg sodium pentobarbital. The hearts were then excised and moved to an isolated heart apparatus as described above. trhe hearts were then subjected to 25 minutes to global ischemia and 30 minutes of `
reperfusion. Time to contracture, recovery of 10 contractile function, coronary flow and cumulative -~
LDH release were measured as described above. ~-~
Time to contracture data are shown in Figure 4. As can be seen parachlorophenyltalanine~(PCPA) .
significantly incareased the time to contracture in these hearts, indicating a protective effect. The effect of parachlorophenylalanine on pre-ischemic and post-ischemic cardiac function and coronary flow is shown in Table 5.
~ 5 30 Min. Post~
Pre-Ischemia Ischemia ~ (beat~min Vehicle 257ilO 200+35a ~ :~
PCPA 271+8 275+8b ~VDP (mmH~
Vehicle 139+3 18ilt~
PCPA 128ill 60i7a,b Corona~y Flow (mL/min/~) Vehicle 16il 9ila PCPA 18il 18*2b LD~ ~ ( u / c~ ) Vehicle - 21~2 PCPA - 15i2b .~ .
~,t ~ t ~7~ t~ ~ t~t~t~ !i t~ ~ t~ ,t~
.
2i~245 ,, All values are mean +SE; HR=Heart Rate;
LVDP = Left Ventricular Developed Pressure a Significantly different from its respective predrug value ~P<0.05J
5 b Significantly different from its respective vehicle groups (P<0.05) The reperfusion bradycardia and contractile -dysfunction observed in vehicle treated hearts was significantly attenuated by parachlorophenyl-alanine. Also shown in this Table 5 iS LDH release during reperfusion, which was slightly, but significantly reduced by parachlorophenylalanine.
Effect of SHT2 Antagonists on alphal Adrenoceptors in Vascular Smooth MUscl~
In order to determine the alphal blocking potency of cinanserin, ketanserin and LY 53857, their effect on methoxamine induced aortic constriction was determined. Male Sprague-Dawley rats were sacrificed using C02. Aortic rings ~3 mm in width) were cut, denuded of endothelium by gently rolling the rings on moistened filter paper, and mounted on stainless steel hooks in 20 mL
muscle chambers containing oxygenated physiological salt solution (PSS) of the ~ollowing composition (in mN): 118.4 NaCl, 4.7 KCl, 1.2 MgSO4, 1.2 RH2PO4, 1.9 CaCl2, 25.0 NaHCO3, 10.1 D-glucose, and 0.01 mM Na2EDTA maintained at 37C. The hooks were connected to Grass FT03C transducers for recording of isometric force development. The rings were stretched to 2 g preload during the equilibration period. During equilibratio~ the rings were periodically stimulated with 2~ mM RCl to determine .. . . . . . . .
21~82~
contractility. The effectiveness of endothelial removal was confirmed by the absence of relaxation by 1 ~M acetylcholine of a contraction in response to 0.01 ~M phenylephrine. ;
s various concentrations of the test compounds were then added to individual baths and allowed a - -~
45 minute incubation before cumulative concentration response curves for methoxamine ~
nM-30 ~M) were obtained. Solvent controls were run in parallel. The compounds tested were 0.3-10 nM
prazosin (n = 4-8 per group), 0.1-10 ~M ketanserin (n = 4-8 per group), 1-lO0 ~M cinanserin (n = 4 per group), or 10-100 ~M LY 53857 (n = 4 per group).
The data were plotted as the mean+SE of at least 4 ~ -15 tissues from different animals. ;~
As shown in Figure 5A, prazosin shifted the methoxamine-tension curve to the right starting at ~ ~ -a concentration of 1 nM. The rightward shift did ~ ~
not appear to be clearly competitive. Ketanserin ~i-20 ~Figure 5B) significantly shifted the curve as ;~
well, although this was significant starting at th2 0.3 ~M concentration. Ketanserin appeared to inhibit methoxamine-induced contractions in a competitive fashion. Both cinanserin and LY 53857 ~Figures 5C and 5D, respectively) produced rightward shifts, but this was not clearly concentration related. Neither compound seemed to have an effect on methoxamine-induced contractions until 30-100 ~M concentrations were reached and then significant inhibition was observed, although maximal effects were reduced.
Despite a lack of blood perfusing the hearts, cinanserin, ketanserin and LY 53857 al~
significantly protected the hearts in this study.
~A616 210824~
Cinanserin appeared to be slightly more potent as a cardioprotective agent relative to the other ;~ -compounds in terms of their ability to increase ~--time to contracture during ischemia, although in general their EC2s values were similar. All compounds increased time to contracture indicating that at least some of their protective effects occured during ischemia per se. All of the 5HT2 antagonists improved the recovery of contractile function during reperfusion, but infusion of ketanserin only during reperfusion did not result in a protective effect, further suggesting that the protective effects of 5HT2 antagonists occur during the global ischemia itself. LY 53857, an octahydroquinoline derivative is structurally distinct from the piperdine 5H~2 antagonists cinanserin and ketanserin and is still equivalent in antiischemic potency.
It was also determined if depletion of 5HT
using parachlorophenylalanine could result in cardioprotection. Parachlorophenylala~ine exerted significant cardioprotective effects which were similar in magnitude to that observed for the 5HT2 receptor antagonists. This is further evidence 25 that antagonism of SHT activity is the mechanism of ~ ~-action of the agents tested herein. These data agree with previous findings in which rat hearts have been found to have measurable levels of 5HT
and that they can accumulate 5HT at neuronal and nonneuronal sites.
In summary, 5HT2 receptor antagonism in isolated rat hearts result8 in significant cardioprotection which seems to occur during ischemia and does not attenuate reperfusion damage.
Effect of SHT2 Antagonists on alphal Adrenoceptors in Vascular Smooth MUscl~
In order to determine the alphal blocking potency of cinanserin, ketanserin and LY 53857, their effect on methoxamine induced aortic constriction was determined. Male Sprague-Dawley rats were sacrificed using C02. Aortic rings ~3 mm in width) were cut, denuded of endothelium by gently rolling the rings on moistened filter paper, and mounted on stainless steel hooks in 20 mL
muscle chambers containing oxygenated physiological salt solution (PSS) of the ~ollowing composition (in mN): 118.4 NaCl, 4.7 KCl, 1.2 MgSO4, 1.2 RH2PO4, 1.9 CaCl2, 25.0 NaHCO3, 10.1 D-glucose, and 0.01 mM Na2EDTA maintained at 37C. The hooks were connected to Grass FT03C transducers for recording of isometric force development. The rings were stretched to 2 g preload during the equilibration period. During equilibratio~ the rings were periodically stimulated with 2~ mM RCl to determine .. . . . . . . .
21~82~
contractility. The effectiveness of endothelial removal was confirmed by the absence of relaxation by 1 ~M acetylcholine of a contraction in response to 0.01 ~M phenylephrine. ;
s various concentrations of the test compounds were then added to individual baths and allowed a - -~
45 minute incubation before cumulative concentration response curves for methoxamine ~
nM-30 ~M) were obtained. Solvent controls were run in parallel. The compounds tested were 0.3-10 nM
prazosin (n = 4-8 per group), 0.1-10 ~M ketanserin (n = 4-8 per group), 1-lO0 ~M cinanserin (n = 4 per group), or 10-100 ~M LY 53857 (n = 4 per group).
The data were plotted as the mean+SE of at least 4 ~ -15 tissues from different animals. ;~
As shown in Figure 5A, prazosin shifted the methoxamine-tension curve to the right starting at ~ ~ -a concentration of 1 nM. The rightward shift did ~ ~
not appear to be clearly competitive. Ketanserin ~i-20 ~Figure 5B) significantly shifted the curve as ;~
well, although this was significant starting at th2 0.3 ~M concentration. Ketanserin appeared to inhibit methoxamine-induced contractions in a competitive fashion. Both cinanserin and LY 53857 ~Figures 5C and 5D, respectively) produced rightward shifts, but this was not clearly concentration related. Neither compound seemed to have an effect on methoxamine-induced contractions until 30-100 ~M concentrations were reached and then significant inhibition was observed, although maximal effects were reduced.
Despite a lack of blood perfusing the hearts, cinanserin, ketanserin and LY 53857 al~
significantly protected the hearts in this study.
~A616 210824~
Cinanserin appeared to be slightly more potent as a cardioprotective agent relative to the other ;~ -compounds in terms of their ability to increase ~--time to contracture during ischemia, although in general their EC2s values were similar. All compounds increased time to contracture indicating that at least some of their protective effects occured during ischemia per se. All of the 5HT2 antagonists improved the recovery of contractile function during reperfusion, but infusion of ketanserin only during reperfusion did not result in a protective effect, further suggesting that the protective effects of 5HT2 antagonists occur during the global ischemia itself. LY 53857, an octahydroquinoline derivative is structurally distinct from the piperdine 5H~2 antagonists cinanserin and ketanserin and is still equivalent in antiischemic potency.
It was also determined if depletion of 5HT
using parachlorophenylalanine could result in cardioprotection. Parachlorophenylala~ine exerted significant cardioprotective effects which were similar in magnitude to that observed for the 5HT2 receptor antagonists. This is further evidence 25 that antagonism of SHT activity is the mechanism of ~ ~-action of the agents tested herein. These data agree with previous findings in which rat hearts have been found to have measurable levels of 5HT
and that they can accumulate 5HT at neuronal and nonneuronal sites.
In summary, 5HT2 receptor antagonism in isolated rat hearts result8 in significant cardioprotection which seems to occur during ischemia and does not attenuate reperfusion damage.
Claims (10)
1. A method for treating myocardial is-chemia in a mammalian species, which comprises ad-ministering to a mammalian species in need of such treatment an effective amount of a serotonin recep-tor antagonist.
2. The method as recited in claim 1 where-in said serotonin receptor antagonist is a 5HT2 re-ceptor antagonist.
3. The method as recited in claim 1 where-in said serotonin receptor antagonist is cinanser-in.
4. The method as recited in claim 1 where-in said serotonin receptor antagonist is ketanser-in.
5. The method as recited in claim 1 where-in said serotonin receptor antagonist is LY 53857.
6. A pharmaceutical composition for use in treating myocardial ischemia in a mammalian spec-ies which comprises an effective amount of a seroto-nin receptor antagonist together with a pharmaceuti-cally acceptable carrier therefor.
7. A composition as claimed in claim 6 wherein said serotonin receptor antagonist is a 5HT2 receptor antagonist.
8. A composition as claimed in claim 6 wherein said serotonin receptor antagonist is cin-anserin.
9. A composition as claimed in claim 6 wherein said serotonin receptor antagonist is ket-anserin.
10. A composition as claimed in claim 6 wherein said serotonin receptor antagonist is LY
53857.
53857.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US97143792A | 1992-11-04 | 1992-11-04 | |
| US971,437 | 1992-11-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2108245A1 true CA2108245A1 (en) | 1994-05-05 |
Family
ID=25518391
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002108245A Abandoned CA2108245A1 (en) | 1992-11-04 | 1993-10-12 | Method for treating myocardial ischemia employing serotonin receptor antagonists |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0596449A3 (en) |
| JP (1) | JPH06211693A (en) |
| AU (1) | AU5041793A (en) |
| CA (1) | CA2108245A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5021428A (en) * | 1985-07-02 | 1991-06-04 | Merrell Dow Pharmaceuticals Inc. | Novel chemical compounds for the prophylactic treatment of migraine |
| CA1280421C (en) * | 1985-07-02 | 1991-02-19 | Albert A. Carr | 1,4-disubstituted piperidinyl derivatives |
| ES2064530T3 (en) * | 1989-06-05 | 1995-02-01 | Daiichi Seiyaku Co | TRIAZINE OR HETERO-CYCLE TRIAZOLE COMPOUNDS WITH SEROTONIN 2-RECEPTOR ANTAGONIST ACTIVITY. |
-
1993
- 1993-10-12 CA CA002108245A patent/CA2108245A1/en not_active Abandoned
- 1993-11-02 JP JP5274232A patent/JPH06211693A/en not_active Withdrawn
- 1993-11-02 EP EP19930117728 patent/EP0596449A3/en not_active Withdrawn
- 1993-11-03 AU AU50417/93A patent/AU5041793A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| AU5041793A (en) | 1994-05-19 |
| EP0596449A3 (en) | 1994-09-07 |
| EP0596449A2 (en) | 1994-05-11 |
| JPH06211693A (en) | 1994-08-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4934048B2 (en) | New uses for cannabinoids | |
| US6617337B1 (en) | Use of nitroxides for the treatment of essential hypertension | |
| KR960008230B1 (en) | Compositions for inhibition of disorders associated with oxidative damage | |
| US20010036939A1 (en) | Zinc ionophores as therapeutic agents | |
| JP2004503585A (en) | Drug mixture | |
| EP0590072A1 (en) | Use of spin trapping for the treatment of diseases associated with oxidation of lipids and proteins | |
| US20100160367A1 (en) | Pharmaceutical compositions containing pyrroloquinoline quinone and nephroprotectant for treating ischemia reperfusion injuries | |
| JPH11501282A (en) | Epibatidine and its derivatives as cholinergic agonists and antagonists | |
| IE64064B1 (en) | Compositions and their use in lowering intraocular pressure | |
| WO1994003171A1 (en) | Cardiac protective | |
| JPH07502730A (en) | Pharmaceutical composition and method for preparing the composition | |
| CA1261272A (en) | Dihydropyridine combination product | |
| EP0351767A2 (en) | Use of potassium channel activators to inhibit myocardial cell necrosis and to maintain the functioning of the heart during myocardial ischemia and/or reperfusion | |
| US20030139387A1 (en) | Compositions and methods for treatment of neurological disorders | |
| HU212945B (en) | Process for producing of pharmaceutical compositions comprising 1-[2-(2-naphtyl)-ethyl-4-(3-trifluoromethylphenyl)-1,2,3,6-tetrahydropyridine or its salts | |
| KR0163840B1 (en) | Inhibition of smooth musclo cell migration by (r)-amlodipine | |
| JP2002114683A (en) | Therapeutic composition comprising excessive enantiomer | |
| US5681845A (en) | DMPO spin trapping compositions and methods of use thereof | |
| US5364857A (en) | Combination having a neuroprotective effect | |
| EP0547558B1 (en) | Use of aminoguanidine for the manufacture of a medicament for inhibiting nitric oxide formation | |
| US5512592A (en) | Method of producing cardiotonic effect and improving cardiac contractile function by administration of carnosine | |
| CA2108245A1 (en) | Method for treating myocardial ischemia employing serotonin receptor antagonists | |
| KR100219972B1 (en) | Method of reducing tissue damage associated with ischemia | |
| US20050267143A1 (en) | Pyrroloquinoline quinone drugs for treatment of cardiac injury and methods of use thereof | |
| EP1750805A2 (en) | Pyrroloquinoline quinone drugs for treatment of cardiac injury |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 19971014 |